Draw-off device for narrow fabric looms

ABSTRACT

The invention relates to a draw-off device comprising elastic belts ( 1, 2 ) for producing curved woven composites on narrow fabric looms. The draw-off device consists of two respective circulatory endless belts ( 1, 2 ), each of which is guided around a driving roller ( 3, 4 ) and a deflecting roller ( 5, 6, 7, 8, 9, 10 ). In addition to the driving rollers ( 3, 4 ), the edge regions of the belts ( 1, 2 ) also have extension drive mechanisms ( 11, 12, 13, 14 ) that only engage with the outer edges of said belts ( 1, 2 ). The belts ( 1, 2 ) preferably have a cross-denticulation which is located on the edges of the sides facing the driving rollers ( 3, 4 ), or which is continuous. The side of the belts facing away from the driving rollers is preferably structured. The radius of curvature of the woven composites can be adjusted by modifying the rotational speed differential between the extension drive mechanisms ( 11, 12, 13, 14 ) and the driving rollers ( 3, 4 ). It is not necessary to stop the loom in order to adjust the direction and radius of curvature.

[0001] The present invention relates to a withdrawal apparatus with elastic belts for the production of curved woven composites on narrow material looms.

[0002] DE 198 16 666 A1 discloses the production of strips as woven composites having a curve in the plane of the weave. Additionally, this document discloses a device for the production of curved strips by which the withdrawal of the warp materials is effected by three differently configured transport belts. The warp material can be used for the purpose of the production of flat cable forms comprised of electrical, pneumatic or optical lines.

[0003] One transport belt is needed for producing a curve in the clockwise direction, another transport belt for producing a curve in a woven portion in a counter clockwise direction, and a further transport belt for producing a straight woven portion. The transport belts for producing the woven portions having a curve are trained around conical change of direction rollers.

[0004] The above-described solution suffers from the disadvantage that, in order to change the direction of the curves, a different transport belt must be positioned for drawing off the respective warp material which is to be handled. In this connection, it is necessary that the ongoing material processing is interrupted, that the existing woven composite is fixedly clamped, that the presently working transport belt is unclamped and removed from the working position, and that the new transport belt is disposed in the working position and engages the warp material by clamping, before the material processing can again be started.

[0005] This disadvantageously influences in a strong way the productivity of the loom or weaving machine. Moreover, a variation of the curvature radius of the curved portion of the woven composite is only possible within very limited boundaries. The deployability of the device for the production of flat cable forms is, therefore, only possible within a limited measure.

[0006] The present invention provides a solution to the challenge of overcoming the disadvantages of the state of the art, and to provide a withdrawal apparatus operable to change the sense or handedness of curvature or the curvature radius without changing the transport belts.

[0007] In accordance with the present invention, this challenge is solved in that the withdrawal apparatus is comprised respectively of two circulating, endless loop elastic belts, each of which is trained around a drive roller and a change of direction roller, whereby the belts comprise, in addition to the drive rollers, expansion drives on both sides of the edge regions of the belts which only engage the outer edges of the belts.

[0008] The belts preferably comprise, on the edge regions, a transverse tooth structure on the sides thereof trained around the drive rollers, or continuously along the edge regions. In a special embodiment of the invention, the belts, on the sides thereof facing away from the drive rollers, are structured with geometric projections and recesses.

[0009] The change of direction rollers comprise, according to one embodiment of the invention, roller plates or discs which are independently rotatable individually one from another. The axes of the change of direction rollers can be spring-cushioned in their mountings.

[0010] The present invention is described in more detail hereafter in connection with the accompanying descriptions of the embodiments thereof. In the associated drawings, it can be seen:

[0011]FIG. 1 is a side view of one embodiment of the withdrawal apparatus of the present invention;

[0012]FIG. 2 is a view taken along line A-A in FIG. 1;

[0013]FIG. 2 is a view of the withdrawal apparatus with the right and left expansion drives of a belt operating at the same speed; and

[0014]FIG. 4 is a view of the withdrawal apparatus with the right and left expansion drives of a belt operating at differing speeds.

[0015] As can be seen in FIG. 1, the withdrawal apparatus is comprised of an upper belt 1 and a lower belt 2. Both belts are comprised of an elastic material such as, for example, rubber. Each belt is trained around a drive roller 3, 4, respectively, as well as around three change of direction rollers, 5, 6, 7 or 8, 9, 10 respectively. The axis of the change of direction roller 5 or 8, respectively, which is in opposed position relative to the drive roller 3 or 4, respectively, is mounted in a spring cushioned manner. The change of direction rollers 5, 6, 7, 8, 9, 10 each are comprised of individual roller discs independently rotatable relative to one another. The belts 1, 2 are, on the sides thereof oriented toward the drive rollers 3, 4, respectively, formed of a fine tooth structure, which is not illustrated, and the drive rollers 3, 4 are, as well, formed with a fine tooth structure.

[0016] Additional expansion drives are provided along the edges of the belts which are, as well, formed with a fine tooth structure. Only the left expansion drives 11, 12 are shown in FIG. 1. In FIG. 2, the left expansion drive 11 and the right expansion drive 13 of the upper belt 1 are shown. As seen in FIG. 2, the expansion drives of the lower belt are arranged in an analogous manner relative to the lower belt.

[0017] A support roller 15 or 16 for each belt is disposed between the drive rollers and the expansion drives.

[0018] The oncoming woven composite, traveling from a not-illustrated weaving machine, travels thereafter between the belts 1, 2.

[0019] The belts 1, 2 are driven by the drive rollers 3,4, respectively, in a uniform manner over their width (compare FIG. 3-in that figure, only the lower belt is illustrated). The drive rollers 3, 4 are adjusted such that the woven composite traveling therebetween is engaged in a clamped manner by the drive rollers. A slight dimensional projection and relief structuring of the belts supports, in this manner, the engagement of the woven composite.

[0020] The region of the clamping of the material begins at the run off point of the belts 1, 2 from the drive rollers 3, 4, respectively. Additionally, the expansion drives 11, 12, 13, 14 engage the belts, each expansion drive engaging only a respective one of the outer edges. All expansion drives operate with the same circumferential speed or velocity as the drive rollers. A straight portion of the woven composite is thus produced. Upon the passage of a given time unit, a length of material s_(l) has been withdrawn. (FIG. 3)

[0021] In order to produce a curved portion of the woven composite, the expansion drives on one side of the belts 1, 2 are driven with a relatively higher velocity or speed than the drive rollers. This process step is schematically shown in FIG. 4, whereby, in the interest of an improved depiction of the invention, only the lower belt is illustrated. In this connection, the left expansion drives 11, 12 are driven with a somewhat higher speed than the drive rollers 3, 4. In this manner, the belts are expanded or extended on that side, which leads to the result that, on this side, the clamped warp threads are withdrawn within the given time unit by a length s_(a)>s_(l). In this manner, a curvature is created in the right hand direction. The cushioned mounting of the change of direction rollers, 5, 8 ensures that the belts are not thrown out or disengaged outwardly during the expansion process. The selection of the sense of direction of the curvature is effected by an increase in the rate of rotation of the respective expansion drive disposed on the opposite side of the woven composite relative to the sense of curvature.

[0022] If a curve is to be produced extending to the left, the left expansion drives 11, 12 are again adjusted to be driven at the same speed as the speed of the drive rollers 3, 4. In contrast, the right expansion drives 13, 14 are accelerated.

[0023] The radius of curvature can be adjusted by varying the rate of rotation differences between the expansion drives and the drive rollers.

[0024] An adjustment of the sense of direction of the curve or the radius of curvature does not require that the weaving machine be stopped.

OVERVIEW OF REFERENCE NUMERALS

[0025]1 upper belt

[0026]2 lower belt

[0027]3 drive roller

[0028]4 drive roller

[0029]5 change of direction roller

[0030]6 change of direction roller

[0031]7 change of direction roller

[0032]8 change of direction roller

[0033]9 change of direction roller

[0034]10 change of direction roller

[0035]11 expansion drive

[0036]12 expansion drive

[0037]13 expansion drive

[0038]14 expansion drive

[0039]15 support roller

[0040]16 support roller 

1. A withdrawal apparatus with elastic belts for the production of curved woven composites on narrow material looms, characterized in that the withdrawal apparatus is comprised respectively of two circulating, endless loop elastic belts, each of which is trained around a drive roller and a change of direction roller, whereby the belts comprise, in addition to the drive rollers, expansion drives on both sides of the edge regions of the belts which only engage the outer edges of the belts.
 2. A withdrawal apparatus according to claim 1 and 2, characterized in that the belts preferably comprise, on the edge regions, a transverse tooth structure on the sides thereof trained around the drive rollers.
 3. A withdrawal apparatus according to claim 1 and 2, characterized in that the belts, on the sides thereof facing away from the drive rollers, are structured with geometric projections and recesses.
 4. A withdrawal apparatus according to claim 1 and 2, characterized in that the change of direction rollers comprise roller plates or discs which are independently rotatable individually one from another.
 5. A withdrawal apparatus according to claim 1 to 4, characterized in that the axes of the change of direction rollers are spring-cushioned in their mountings. 